To keep confidentially of digital material people use password to block unauthorized person to access to that material, typical secure material can be: access to computer, unlock mobile phones, open confidential files, online banking, online payment, mobile payment, open the entrance door to home or office, etc.
In order to access to that secure material, the user needs to type the correct password. In some cases, there is a special card like a credit card that the user needs to slide it or to locate it near to the card reader. The card reader identifies if the card holder has permission to access to the confidential material or not. In some other cases people use fingerprint to enable access. In this case the user need to put his relevant finger on a fingerprint reader which analyzes and identifies if the fingerprint of the user is valid and has permission to access. All this kind of access procedures are very inconvenient. For example; In case of typing password, most of the people use different passwords for different accounts which means that the user needs to remember different password for different access points, which can be very annoying. In case of credit card most of people hold it in their wallet and in order to use it, they need to find the relevant card and slide it on the access reader.